
Sonic: After the Sequel (shortened to Sonic ATS) is a fan-made game developed by LakeFeperd, designed to explore the events that might have occurred between Sonic the Hedgehog 2 and Sonic 3 & Knuckles. In the game, players take control of Sonic and Tails as they race through various zones to stop Dr. Eggman from launching the Death Egg at—and attacking—a newly discovered, enigmatic island called Angel Island. It follows the story of Sonic Before the Sequel.
Following the events of *Sonic 2*, Sonic is captured by Tails, who is flying the Tornado. The pair spots an island with a massive metal ring floating near a snowy mountain peak. Curious, they land to explore this mysterious new location. After navigating through Horizon Heights, Sonic comes across a small robot that looks like Tails. The machine powers on and attacks him. After a short battle, it's revealed to be an ambush set by Eggman. Sonic is ensnared in a magnetic force field, unable to stop the doctor from seizing the Chaos Emeralds. Just as Eggman is about to claim them, Tails shoves the emeralds aside, sending them back to the Special Zone. Enraged, Eggman flees to his temporary base, Storm Station Zone, with Sonic and Tails hot on his trail.